Flashcards in Midterm 1 Deck (110):
what are the unifying themes
1. Laws of Chemistry and Physics
2. Relationship between genotype and phenotype 3. Physiology is matched to its environment
4. Relationships between structure and function
5. Homestasis- feedback and control
What is Kroghs principle
For every biological system, there is an organism on which is can be studied.
ex. drosphila, squid giant axon
Function of all living things
1. Respond to environmental changes
3. Growth and reproduction
4. capable of some degree of movement
5. life functions require energy
What are the two Chemisty laws
Thermodynamic and Kinetics
What is Adaptation
Process of evolution through natural selection over many generations of altering allelic frequencies leading to better characteristic which match the environment
What is Homeostasis and how is it controlled
Maintaining internal conditions while external conditions change.
Positive and negative feedback loops
What is a positive feedback loop?
Initial stimulus changes response to enhance change in original condition. ex. blood clotting
what is Negative feedback loop?
Maintaining things like temperature, pH, hormones
Four tissue types of tissue
Epithelial, Connective, Muscle and Nerve
What are the types of epithelial tissue
apical v.s basil (attach to membrane)
mesenchymal ( irregular shape that is not anchored)
What is connective tissue
lower proportion of cells but lots of ECM
What is muscle tissue used for and what are the types
Movement, locamotion, internal temperature
1. skeletal ( striated, voluntary control)
2.Cardiac (striated, non-voluntary)
3. Smooth (Non-striated, non-voluntary)
What are the nine abdominal regions
L-R Hypochondriac, Epigastric, R-L lumbar, Umbilical, L-R Inguinal, Hypogastric
What are the 11 organ systems
Cardiovascular/circulatory, Digestive/excretory, Endocrine, Integumentary, Lymphatic/ immune, Muscular, Nervous, Renal/urinary, Reproductive, Respiratory, Skeletal
Receives incoming information (senses). Sends messages to the body about how to react.
Provides Shape and structure to the body. Allows for movement. Protects vital organs. Produces blood cells.
Protects the body from invaders by providing a tough protective layer. Warms the body. Cools the body.
Allows for movement of the body. Keeps head in position. Provides heat.
Controls body functions using chemicals messengers called hormones.
Transports oxygen, waste, nutrients, hormones, heat, etc... around the body
Brings oxygen into the body. Gets rid of carbon dioxide.
Cleanses the blood. Rids the body of wastes. Maintains salt and water balance.
Breaks down food into smaller molecules. Absorbs these nutrients into the body.
Produces sex cells (sperm and eggs). Produces sex hormones (testosterone, estrogen). Nurtures the unborn baby (fetus).
What does the Autonomic nervous system control
Smooth muscle, cardiac muscle, glands and adipose tissue
4 functional zones of neurons
Signal reception, signal integration, signal propegation, and signal transmission
What is signal reception
Resting potential, occurs on dendrites, changes in membrane potential allow for ions to move
what is signal integration
Graded potential. Very localized. Vary in magnitude. Use decrement (electrotonic spread)
What is signal propagation
Action potential. Long distance signals
What is signal transmission
Synaptic activity. release of neurotransmitters
What is needed to create voltage differences
Concentration gradient of ions and permeable membranes
What is a chemical gradient
concentration gradient of ions
What is electrical gradient
attraction or repulsion of charges
what is equilibrium potential
When both chemical and electrical are occuring resulting in no net movement of ions
Na and Cl are higher in...
Cytosol has lots of
K, and negative charged proteins
When is Goldman equation used
When multiple ions contribute to resting membrane potential.
Based on concentrations and permeability of ions or the sum of equilibrium potentials
What is equilibrium potential
Each ions own equilibrium based on its concentration gradient.
Is the same as Vm
Calculated using nernst equation
What is electromotive force
Seperation of charge that drives ions to move.
positive means going out of the cell
negative means going into the cell
What is a neuron?
generating a signal, morphological specialization and polarity
What are the 4 types of Neurons
Anaxonic, Bipolar, Unipolar, Multipolar
What is an anaxonic neuron
no axon, non-spiking interneuron that works through graded potential, not action potential
What is a bipolar neuron
Found in special sensory organs like retina. quick signals that don't need more than 2-3mm to travel to cell body
What is a unipolar neuron
Single process that splits from cell body, dendrites and axon terminal are continuous, action potential occurs at dendrites
What is a multipolar neuron
Most common one to look at, one axon with multiple dendrites, very long
What are the three neuron functional types and decribe them
Sensory- 10 billion, unipolar, afferent
Interneurons- 20 billion, all in spinal cord, mostly multipolar
Motor neuron- 0.5 million, efferent, muscles
What are the 4 types of neuroglia in the CNS
Ependymal, Microglia, Astrocytes, Oligodendrocytes
What are ependymal glia
Line the ventricles and have cilia-like structure. CFS (chroid plexus)
what are microglia
Originate outside the CSF, act as mobile phagocyte and target cell waste, cause inflammation in the brain, comes from the blood making it similar to monocytes and macrophages
what are astrocytes
help maintain the BBB due to tight junctions, regulate ions, nutrients, and gases in contact with neurons, Calcium waves get through junctions and release glutamate and ATP
What are the two types of astrocytes
Fibrous (white matter) and Protoplasmic (grey matter)
What are oligodendrocytes
act as insulation (increasing transmission) and structural roles/stability of axon, 40% water, layer of protein and two layers of membrane.
What are the types of neuroglia in PNS
Schwann cells and satellite cells. Both can act as neurolemma
what are schwann cells
myelinate axon (1 schwann=1 cell) or multiple unmyelinated axons can be bundled up together in 1 schwann cell
multiple cells around glial cell body, regulate intercellular environment, can allow for chronic pain to stay
What is Gullian barre syndrome
autoimmune attack on the myelin, without myelin axon cant conduct
What are the three types of gated channels
Chemically gated channels, Voltage-gated channels, Mechanically gated channels
Depolarization occurs when
sodium ions rush out of cell
repolarization occurs when
when Na stops or K rushes into cell
What is the time constant
T=RC, it is the time it takes to reach Vmax.
0.37, which is the point of decay which we compare to other neurons
What are the characteristic of graded potential
Small (0.5-1mV), very localized, spread by electrocurrent spread (ions repelling eachother)
What are the two types of post synaptic potentials
What is EPSP
Excitatory post synaptic potential, increases the probability a cell will fire, Vm moves towards zero, depolarization
What is IPSP
Inhibitory post-synaptic potential, decreases likelyhood of firing, hyperpolarization
What is summation
The combination of EPSP and IPSP
Can be spatial (same time in same area) and temporal (repeated firing builds on each other)
What is the axon hillock
a site where neurons integrate the excitatory and inhibitory stimuli
What are the 4 steps of action potential
1. graded potential brings it to threshold
2. Voltage-gated ion channels for sodium begin to open causing more to open
3. Sodium starts to close and K+ start to open causing an efflux stronger than influx.
4. K+ channels taken a while to open resulting in hyperpolarization.
What are the two types of action potential propagation
Continuous propagation: 1 m/s, short distances
Saltatory propagation: big jumps in action potential, myelin gaps
What is the Hodgkin-Hoxel cycle
where action potentials keep firing down the axon
What is length constant
How far an electrotonic current can spread and still fire an action potential. is highest when resistance of cell membrane in high and resistance of extracellular and intracellular fluid is low
What three things affect length constant
Resistance of cell membrane, Resistance of intracellular fluid, Resistance of extracellular fluid
How does myelin affect propagation
It increases propagation because it prevents current loss and decreases current velocity
What are the 3 steps of the refractory period
1. Channel closed ( activation gate is closed but inactivation gate is open)
2. Channel open (Both are open and current goes through)
3. Channel inactivation (AG stays open but IG closes and NA+ influx stops)
Which channels determine firing frequency and refractory period?
What is absolute refractory period
No signals can be fired
what is relative refractory period
when membrane can respond to only large stimuli (when subpopulation starts)
Refractory period prevents...
action potential from going both ways
What is synaptic activity
Electrical signal is transmitted directly as electrical signal or after is turns into chemical signal
Vesicle movement and activity can be effected by
What are synaptotagmin
Result in the release of calcium, opening channels and causing fusion of membrane so the neurotransmitters can get released.
Can act as both zipper mechanism and fusion
What are SNARES
family of proteins on vesicles which include synaptobrevin (VAMP)
What are the two types of T-SNARES
SNAP25 and Syntaxin, which both bring vesicles in contact with presynaptic membrane
What is the zipper mechanism
proteins pulling vesicle towards the membrane. these include SNAP25, Syntaxin, and Synaptobrevin (VAMP)
What is the kiss and run hypothesis
vesicles dont fully fuse, just open channel to release neurotransmitters.
very fast method
What is the current theory for vesicles
Both kiss and run, and endocytosis occur
does K have AG and IG
Exocytosis is mediated by what
SNARE, VAMP, syntaxin, SNAR25
What is the concept of full fusion
clathrin cluster together, which is very slow
bulk endocytosis which has lots of vesicles fusing at the same time
What are the 5 types of neurotransmitters and examples of them
1. Acetylcholine (primarily direct, bind to ion channels)
2. Biogenic (dopamine)
3. Amino acids (GABA)
4. Neuropeptides (CART, somatostatin)
5.the rest (ATP, Nitric oxide)
What Are the criteria for neurotransmitters
1. Produced in neurons
2. Released upon depolarization
3. bind to receptor on postsynaptic, influence neuron and needs to be turned off
what are the three fates of neurotransmitters
2. Diffusion in post synaptic neuron
What is neurotransmitter reuptake
non-specific reuptake where neurotransmitter gets pulled in
Amines have specific transporters (Dopamine has dopamine A transporter which repackages dopamine)
Is diffusion of neurotransmitter quick?
No, the synpase is very thick
how does neurotransmitter degradation occur
post synaptic neuron produce proteins
what is synpatic fatigue
when a constant stimulus is occuring and uptake and synthesis of neurotransmitters is too slow
What is quantal release
Each vesicle has the same amount of neurotransmitter but different amount of vesicles are released
what is myasthenia gravis
muscle weakening, when there are either too many degradation enzymes or not enough postsynaptic receptors
What neurotransmitter are associated with depression and OCD
reduction of serotonin and 5HT
What are junctional folds
increased surface area and only occur in neuromuscular junctions
what are the two types of receptors
Ionotropic receptor (nAChR)
How do ionotropic receptors work
nicotinic, direct affect on ion channels making it very fast
How do metabotropic receptors work
muscarine, they regulate a 2nd messenger which then affect ion channels making them slow and indirect
What is an example of metabotropic receptor
Gprotein coupled receptors (GPCR) which use cAMP as 2nd messenger
The amplifier enzyme turns ATP in cAMP
What are the dopamine receptors
D1 type: D1 and D5, which boost production of cAMP
D2 type: D2, D3, and D4, which inhibit production of cAMP
GABA is an...
inhibitory transmitter, binds to KCC2
what are the characteristics of an electrical synapse
no gradient, connexins lock and anchor together.
GAP junctions, no synaptic cleft (cytoplasm is continuous) ions flow through without delay
How do you test for electrical synapse
1. Dye coupling: if the dyne continuous into next neuron
2. no synaptic delay, electrical signal can go in both directions or in a single direction
3. calcium free saline. electrical will keep going where chemical will stop